The control of hemorrhage (bleeding) is a critical step in first aid and field trauma care. Unfortunately, the occurrence of excessive bleeding or fatal hemorrhage from an accessible site is not uncommon (J. M. Rocko et al. (1982). J. Trauma 22:635). Mortality data from the Vietnam War indicates that 10% of combat deaths were due to uncontrolled extremity hemorrhage. Up to one third of the deaths from exsanguination during the Vietnam War could have been prevented by the use of effective field hemorrhage control methods. (SAS/STAT Users Guide, 4th ed. (Cary, N.C.: SAS Institute Inc; 1990)).
Although civilian trauma mortality statistics do not provide exact numbers for pre-hospital deaths from extremity hemorrhage, case and anecdotal reports indicate similar occurrences (J. M. Rocko et al. (1982). J. Trauma 22:635). These data suggest that a substantial increase in survival can be affected by the prehospital use of a simple and effective method of hemorrhage control. Unfortunately, such a method has not been successfully demonstrated by use of commercially available hemostatic devices.
Separately, surgical wound closure is currently achieved by sutures and staples that facilitate healing by pulling tissues together. However, very often they fail to produce the adequate seal necessary to prevent fluid leakage. Thus, there is a large, unmet medical need for devices and methods to prevent leakage following surgery, including leaks that frequently occur along staple and suture lines. Such devices and methods are needed as an adjunct to sutures or staples to achieve hemostasis or other fluid-stasis in peripheral vascular reconstructions, dura reconstructions, thoracic, cardiovascular, lung, neurological, and gastrointestinal surgeries.
Most high-pressure hemostatic devices currently on the market are nominally, if at all adhesive. Good examples of such devices are the QuikClot® ACS™ (Z-Medica, Wallington, Conn.) and HemCon™ bandage (HemCon, Portland, Oreg.), the two hemostatic devices currently supplied to members of the US armed forces. The mineral zeolite crystals in the QuikClot sponge cause adsorption of the water molecules in the blood, thus concentrating the clotting factors and accelerating blood clotting. The chitosan mixture that makes up the HemCon bandage has a positive charge and attracts red blood cells, which have a negative charge. The red blood cells are drawn into the dressing, forming a seal over the wound, and stabilizing the wound surface.
The HemCon bandage product mentioned above was developed in an attempt to provide pre-hospital hemorrhage control and has already demonstrated limited success in the field. However, the chitosan network that makes up the HemCon bandage can be saturated with blood and fail quickly when faced with brisk flood flow or after 1-2 hours when confronted with moderate blood flow from a wound (B. S Kheirabadi et al. (2005). J. Trauma. 59:25-35; A. E. Pusateri et al. (2006). J. Trauma. 60:674-682). Also, the HemCon bandage patch is available only as a stiff patch that cannot fit easily into irregular wounds, further limiting its utility.
Other polysaccharide-based hemostatic devices that have been suggested for use in hemorrhage control are RDH™ (Acetyl Glucosamine), TraumaDEX™ (MPH), and Chitoskin™ (Chitosan & Gelatin). However, none of these types of bandages have been able to consistently demonstrate avoidance of failure in the face of significant blood flow. Other recently introduced hemostatic devices include Celox™ (Chitosan Crystals) and WoundStat™ (TraumaCure Inc., MD) (granular blend of smectite mineral and a super absorbent polymer). However, both of these products rapidly swell to fill wound sites, making them appropriate only for accelerating blood clotting in specific types of wounds and presenting a danger of reducing or even eliminating blood flow in surrounding blood vessels.
QuikClot ACS™, also mentioned above, has also demonstrated efficacy in staunching moderate levels of hemorrhage. However, the water adsorption mechanism of mineral zeolite cannot occur without the release of a large amount of heat. As such, application of the QuikClot ACS™ results in high temperatures and severe burns at the injury site, which damage surrounding tissue areas and make later medical care far more complicated (A. E. Pusateri et al. (2006). J. Trauma. 60:674-682). Clearly, a hemostatic solution without this significant side effect is more ideal. While QuikClot has developed a mineral mixture that releases less heat upon application, the efficacy of the cooler mixture is insufficient for serious trauma care. Furthermore, neither the original nor cooler mineral mixtures can stop brisk arterial bleeding.
All of the above-mentioned products rely on the natural clotting cascade to control fluid leakage from a wound site. As such, they are all only useful only for stopping blood flow and each only under conditions appropriate for that particular device. General wound site sealing, particularly of injured sites leaking non-blood fluids, are beyond the scope of these products.